import { O_CREAT } from "constants";

const _get: any = function (obj: any, path: any, defaultValue: any) {
    if (path.substr) path = path.split(/\.|\\|\//);
    if (path.length && obj) {
        return _get(obj[path.shift()], path, defaultValue);
    } else if (!path.length && obj) {
        return obj;
    } else {
        return defaultValue;
    }
};

const _find = function (collection: any, predicate: any) {
    if (!collection) return undefined;
    if (typeof predicate === 'string') {
        for (let item of collection) {
            if (Object.keys(item).indexOf(predicate) > -1) {
                return item;
            }
        }
    } else if (predicate instanceof Array && predicate.length === 2) {
        for (let item of collection) {
            if (Object.keys(item).indexOf(predicate[0]) > -1 && item[predicate[0]] === predicate[1]) {
                return item;
            }
        }
    } else if (Object.prototype.toString.call(predicate) === '[object Object]') {
        for (let item of collection) {
            let r = true;
            Object.entries(predicate).map(([key, value]) => {
                if (item[key] !== value) {
                    r = false;
                }
            });
            if (r) {
                return item;
            }
        }
    } else if (Object.prototype.toString.call(predicate) === '[object Function]') {
        for (let item of collection) {
            if (predicate(item)) {
                return item;
            }
        }
    }
    return undefined;
};

// 没有考虑所有情况，只是适用于此
const _groupBy = (arr: any, value: any) => {
    return arr.reduce((pre: any, cur: any) => {
        const key = cur[value];
        if (pre.hasOwnProperty(key)) {
            pre[key].push(cur);
        } else {
            pre[key] = [cur];
        }
        return pre
    }, {a:1})
}

export default {
    get: _get,
    find: _find,
    groupBy: _groupBy,
}